The story is mostly based on the novel's story:
The player is Paul Atreides, son of Duke Leto Atreides and Lady Jessica. The House Atreides was given an unrefusable offer by the Emperor Shaddam Corrino IV - mine the Spice Melange from the desert planet Arrakis, occupied by their long-time enemies: the House Harkonnen. Duke Leto accepts the offer not only because of the wealth provided by Spice trading, but also to defeat the Harkonnen.
The game, seen always through the eyes of Paul, is a mix between RTS and adventure gaming. While the basis of the game is the strategy component, dialog between characters and a linear plotline give the game more depth than most strategy games. The player is also required to do some miniquests involving talking to characters and traveling to locations, which adds a small adventure game element.
There must be a balance between military and spice mining power. While having a strong military force will provide fast response to the Harkonnen, if Spice isn't mined fast enough to keep up with the Emperor's demands, the game will be lost. However, if there is too much focus on spice mining, Harkonnen troops can ambush a sietch, capturing all troops inside. They can only be rescued if the sietch is liberated. Since the game is as much resource managing as military conquest, balancing both is the key for successful completion.
The Atreides House has no military or spice mining units. Soon in the game, Paul must meet the closest Fremen leaders and convince them to work for him. In the beginning, they will only agree to work as spice miners. After Paul is introduced to Stilgar, the tribes will agree to work as either spice miners or military soldiers as Paul chooses. After he is introduced to Liet Kynes, the tribes can also take ecology as their occupation.
All tribes will increase their ability in their chosen occupation. Spice prospectors do so by spice prospecting in many sietches. Spice miners do so by mining spice. Military troops do so by training in their sietches (if Gurney Halleck is in the same sietch they increase their ability at a faster rate) or successfully completing military missions.
All tribes except the spice prospector tribe can change their occupations, although it is better to keep a tribe in the same occupation. Experienced spice prospectors can prospect spice faster. Experienced spice miners can mine more spice. Experienced military troops are more effective in military missions. However, there may be situations where changing a tribe's occupation is required. For example, if a large number of military troops training in a sietch is captured by Harkonnen forces, more military troops need to be raised from the spice or ecology troops to liberate the sietch and rescue the captured troops.
Although the Fremen agree to work for the Atreides in order to depose the Harkonnen, if there are tribes from both hemispheres in the same sietch, they will quarrel and refuse to work (this seems to happen frequently with the spice miners). Morale (affected by contacts with Paul, Atreides advancement in Arrakis, the progress of ecologists, and whether Chani is captured or free) also affects the speed and capabilities of the tribes.
The Ornithopter (Orni) is the default transport method for Paul until he's able to ride sandworms. With the Fremen, they are used for either moving from one sietch to another quickly or as an early warning against sandworms attacking spice miners and prevent Harvesters from being swallowed. Harvesters increase spice mining speed, and can be either bought from smugglers or found in sietches. Weaponry ranges from crysknives, laser guns, Weirding Modules and the powerful atomics, and are usually found on sietches or conquered Harkonnen fortresses.
The vast majority of all areas are sietches and fortresses, where the battles take place. When one side wins a battle, their troops will transform the structure into their own side (Atreides/Fremen troops transform fortresses into sietches, Harkonnen troops transform sietches into fortresses).
Paul's presence during a battle increases the men's morale. He can boost their morale even more if he comes along on a worm. Once there, he can boost their morale even further more by controlling the battle personally (but then risks dying if the battle is lost). There are two ways for Paul to control the battle personally.
Massive Attack: Paul will order his troops to launch an immediate full scale war.
Fight for a day: Paul will order his troops to reserve their resources and fight for a whole day.
Vegetation raises the morale of Fremen. In addition, planting the vegetation south to the Harkonnen controlled areas, so it will grow north and reaches them, will lower their spice production. Moreover, if enough vegetation grows north into Harkonnen fortresses, they will abandon them. A military unit must still be sent then to take over such fortresses, but there will be no one to fight with.
Nevertheless, it is generally agreed amongst players that ecology is of a lower priority than both spice mining and military, hence most players tend to deploy lesser amount of troops to ecology. However, by having enough vegetation growing north into the Harkonnen Palace, ecology is actually one of the ways to reach the end game.
The game follows loosely in-off-between the book and the 1984 movie by David Lynch (Paul Atreides was designed to look like Kyle MacLachlan, who is actually credited as Paul Atreides). Only a few characters are removed from the movie, clearly the biggest visual inspiration for the game, such as Shadout Mapes, Piter De Vries and Reverend Mother Ramallo. Some characters' roles have changed, however, such as Harah who follows Paul about in the earlier stages of the game.
Dune: Spice Opera was released by Virgin Records in 1992. The tracks were composed by Stéphane Picq and Philip Ulrich. Virgin Records was later sold to EMI, which then became the new holders of the copyright. Picq wishes to have the rights in order to rerelease the album, though they were not granted.